Grinding machine headstock



Patented Apr. 5, 1938 UNITED STATES PATENT OFFICE- auss'cz I I onmnnvo mom nnans'rocx Application January 21,1937. Serial No. 121,316"

This invention relates to machine tools, and more particularly to a headstock for use in grinding machines and the like.

One object of this invention is to provide a simple and thoroughly practical headstock construction for a machine tool. Another object of the invention is to provide a machine tool headstock in which the face plate and center may be readily changed from a live center to a dead center. A further object of the invention is to provide a simplified headstock construction whereby manipulation of a single control member serves readily to shift the headstock from a live center to a dead" center headstock. Other objects will be in part obvious or in part pointed out hereinafter.

The invention accordingly consists in the features of construction, combinations of elements, and arrangements of parts, as will be exemplified in the structure to be hereinafter described, and 20 the scope of the application of which will be indicated in the followingclaims.

In the accompanying drawing, in which is shown one of various possible embodiments of the mechanical features of this invention,

Fig. 1 is a fragmentary front elevation of a. grinding machine embodying the improved headstock;

Fig. 2 is a horizontal sectional view, taken approximately on the line 2-2 of. Fig. 1, on an enlarged scale, showing the details of the head stock construction as a live spindle and center headstock;

Fig. 3 is a fragmentary sectional view of the control mechanism, showing the parts in position to render the spindle and center stationary to produce a dead" center headstock;

Fig. 4 is a fragmentary sectional View, taken approximately on the line H of Fig. 2, showing 40 the key for locking the face plate and spindle so that they rotate together for setting up the headstock as a live" center type; and

Fig. 5 is a fragmentary view, on a reduced scale, of the drive to the headstock spindle, on a reduced scale, taken approximately on the line 5 5 of Fig. 2.

In accordance with one embodiment of this invention, a grinding machine is provided having a base It upon which is slidably mounted a work 50 table II with a headstock l2 adjustably positioned thereon. The base l0 may be provided with a suitable mechanism to reciprocate or traverse the work table II longitudinally relative to the base It and relative to a rotatable grinding wheel i2.

The rotatable grinding wheel I3 is supported on a transversely movable wheel slide H which is arranged to'be moved transversely either toward or from the work table II by means of a manually operable feed mechanism It.

The table Il may be reciprocated longitudinal ly by means of a hydraulically operated mechanism controlled by a reversing lever l6 and a pair of adjustable table dogs ll. A control lever I8 is connected to actuate a speed control and stop 10 and start valve (not shown) The hydraulically operated table reciprocating mechanism is not considered to be part of the present invention and, therefore, hasnot been illustrated in detail. For further details of construction of the'table 15 operating mechanism, reference may be had to the prior United States Patent No. 2,071,677 dated February 23, 1937.

The table ii may be traversed manually, if desired, by means of a manually operable traverse wheel I9 which operates a manually operable table traverse mechanism such as illustrated in the prior United States Patent to Norton et al. No. 1,299,765 of April 8, 1919, which, is suitably connected to a rack (not shown) underneath the work table II to move the same.

In the preferred construction, the headstock comprises a frame or base I2 which is adapted to fit or mate .withthe upper surface of the work table II and to support the other parts of the self-contained electric motor drivenheadstocks To attain the main object of this invention, the headstockis arranged so that it maybe readily used as either a dead center or a live" center type. The headstock l2 comprises acenter 22 mounted in the spindle H which is rotatably supported in anti-friction bearings 22 and 22 in the headstock. A second shaft 25 is mounted in suitable bearings 28 and 21 parallel vwiththe I spindle 2|. A sprocket 22 is mounted on the 40 end of the shaft 25 and is connected by a link chain 29 with a sprocket 30 which is Journaled on anti-friction bearings 2| and'32 on the spindle 2 I. An idler sprocket 23 is rotatably mounted on the end of an arm 34 which is supported on a 45 stud 35 and is arranged tobe locked to the headstock casing by means of a lock nut 36 to facilitate taking up any slack in the driving chain. A plate 40 is fixedly mounted on the sprocket 20 by means of screws 4 I, and a face or driving plate 42 is fastened to the plate 40 by screws ll, so that the driving chain 29 transmits a rotary motion from the shaft 25 and the sprocket 22 to rotate sprocket 30, the plate 40 and the face plate 42.

In the preferred construction, the shaft 25 may be driven by means of a pulley 45 which is fixedly mounted on the end of a rotatable sleeve 46 which is journaled to rotate within-the bearing 26. The pulley 45 is connected by driving belts 46 with a pulley 41 mounted on the outer end of an armature shaft 48 of an electric motor 48. which ls mounted on the upperportion of the headstock |2.

vIn order readily to stop and start the headstock without stopping the motor 48, a suitable clutch mechanism is connected to the pulley 45 and arranged to connect the sleeve 46 with the shaft 25 to transmit a rotary motion thereto. The clutch may be of any suitable type but, as illustrated, comprises a member 55 having an internal cone shaped aperture 56. The clutch member 55 is provided with an integral sleeve 51 which is rotatably supported on the shaft 25 and is slidably keyed by a key 58 to the sleeve 46, so that rotation of the pulley 45 is transmitted through the sleeve 46, the key 58 .and sleeve 51 to rotate the clutch member 55. A movable clutch member 681s slide-bly keyed to the shaft 25 by meansof a key 6|. The clutch member 68 is provided with an external frustoconical surface 62 which is adapted to mate with the internal clutch surface 56 to transmit a rotary motion from the pulley 45 to the shaft 25.,

A compression spring 63 surrounds the shaft 25 and is interposed between a flange 64 carmeans of a pin 66. The spring 63 normally-tends to hold the clutch member 68 in engagement with the clutch member 55. In order to control the movement of the movable clutch member, a manually operable control lever 68 is mounted on the front of the headstock I2 and on the outer end of a rotatable shaft 68. A yoked member 18 is carried by the shaft 68 and is provided with opposed pins 1| and 12 which engage holes in a collar 13 which surrounds a portion of the clutch member 68.

When it is desired to disengage the clutch member 68 from the clutch member 55, the yoked member 18 is rock'ed so that the pins 1| and 12 move toward the right (Fig. 2) which serves to throw the clutch shifting ring 13 into engage- For certain grinding operations, it is desirable.

to utilize a live spindle or live center headstock in which the driving or face plate 42 and the center 48 are rotated together,'so that an adjustable driving pin 88 carried by the face plate 42 will engage a dog 8| which is'clamped on the end portion of a work piece 82, torotate the work piece 82 with the face plate 42 and the center 28. In order readily to connect the spindle 2l'to rotate with the faceplate 42, a clutch is provided comprising a movable clutch member, such as a key 83 mounted on the end of a pin 84 which is slidably supported in the spindle 2|. The movable clutch member or key 83 is arranged to engage a radially extending slot in the end of the spindle 2| and a radially extending slot 86 in the driving plate 48. A

spring81 surrounds the pin 84 and is interposed between a portion 88 of the pin 84 and a sleeve or'bushing88. The spring 81 tends to move the key 88 into engagement with the slots 85 and 86 so that when the clutch is engaged, a rotary motion will be transmitted through sprocket 28, the chain 28, the sprocket 38, the driving plate 48, the face plate 42, the key 83, and spindle 2|, simultaneously to rotate the driving or face plate 42, the spindle 2|-and the center 28.

For other types of grinding, it is desirable to utilize a dead center type of headstock in which the work piece is mounted on a non-rotatable headstock center and the other end supported on a non-rotatable footstock center, while the face plate is rotated to drive the work piece on the fixed or non-rotatable center during the grinding operation. To facilitate setting up the machine for a dead center grinding operation, it is desirable to provide a readily accessible control member whereby by the manipulation of a single control element, the spindle 2| may be disconnected from the driving mechanism and the spindle 2| and center 28 locked against rotation for a dead center grinding operation. A readily accessible knurled knob 88 is mounted on the outer end of a screw 8|. The screw 8| is formed as an integral part of a-plunger 82 which has a frusto-conical end portion 83 adapted 'to mate with a correspondingly shaped hole or depression 84 in the spindle 2|. A floating nut 85 is screw threaded onto the screw 8| and is held against rotation by a key 86. A spring 81 normally holds the nut 85 in the full line position indicated in Fig. 2. When it is desired to lock the spindle against rotation, the screw 8| is turned to move the conical surface 83 ofthe plunger 82 into engagement with the correspondingly shaped depression 84 in the spindle 2|.

with the plunger 83, the screw 8| may be rotated and the end of the frusto-conical portion 88 bears against the periphery of the spindle 2|, and continued rotation of the screw 8| serves to move the nut 85 downwardly (Fig. 2) to compress ,thespring 81 so that when the spindle is rotated so that the depression 84 comes into alignment with the frusto-conical plunger 83, the released tension of the spring 81 will rapidly seat the frusto-conical member 83 in the depression 84, thereby locking the spindle 2| against rotation. I I

At the same time, it is desirable automatically to throw the key 83 out of engagement with the slot 86 so that the driving plate 48 and the face plate 42 may be rotated while the spindle 2| is held locked in a stationary position. This is accomplished by providing a frusto-conical end portion 88 on the end of the pin 88 so that when the frusto-conical portion 83 of the locking pin 82 enters the depression 84, the frusto-conical surface 83 engages the conical surface 88 of the pin 88 and serves to move the pin 88 and key 83 toward the right (Fig. 2) so that it is thrown out of engagement with the radial slot 86 in the plate 48, thereby disconnecting the spindle 2| from the driving plate 48 and allowing free rotation of the face plate 42 while the spindle 2| and the center 28 are held statidnary for a dead center grinding operation.

The operation of the headstock will be readily apparent from the foregoing disclosure. The motor 48 is set in rotation by a well-known control mechanism, such as a push button (not shown). The control lever 68 is then moved to throw the clutch member 68 into engagement with the clutch member 55 to transmit the rotary motion of the motor 48, through the pulley 45, the

If the depression 84 is not aligned auasos belt 46 and the pulley 41 to the shaft 2| to rotate the driving plate 40 and the face plate 42. As shown in Fig. 2, the rotation of the shaft 25 is transmitted to rotate the spindle 2| and the center 20 for a. live spindle or live center grinding operation.

When it is desired to grind a work piece by the dead center method, theknurled knob 90 is rotated to throw the frusto-conical portion 91 of the pin 92 into the position shown in Fig. 3, thereby locking the spindle 2! against rotation and simultaneously moving the driving key 83 out of engagement with the slot 86 in the end of the spindle 2|, so that the spindle 2| and the center 20 are held stationary while the driving plate 40 and face plate 42 are rotated by the motor driving mechanism above described, so that the work piece 82 is rotated on a pair of opposed non-rotatable centers during the grinding operation.

It will thus be seen that there has been provided by this invention apparatus in which the various objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As many possible embodiments may be made of the above invention and as many changes might be made in the embodiment above set forth, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawing is to be interpreted as illustrative and not in a limiting sense.

I claim:-

1. In a machine tool headstock, a base, a rotatable spindle thereon, a work supporting center carried by said spindle, spaced anti-friction bearings to support said spindle, a rotatable face plate, an anti-friction bearing rotatably to support said face plate on said spindle, means to rotate said face plate, and a manually operable clutch which is operative during rotation of the face plate to connect said face plate with said spindle, whereby the spindle and center may be rotated with said face plate.

2. In a machine tool headstock, a base, a rotatable spindle thereon, a work supporting center carried by said spindle, a rotatable face plate, means to rotate said face plate, a movable driving member carried on the end of said spindle, a slot in the face plate which is arranged to mate with said driving member to rotate said spindle and center with said face plate, and manually operable means to move said driving member in a direction parallel to the axis of said spindle during rotation of the spindle to move said member a out of engagement with said slot so that the spindle and center remain stationary while the face plate is rotated.

3. In a machine tool headstock, a base, a rotatable spindle thereon, a work supporting center carried by said spindle, a rotatable face plate. means including a clutch to rotate said face plate, a movable radially extending driving member carried by and adjacent to the end of said spindle, a radially extending slot in said face plate which is arranged to mate with said driving member to rotate said spindle and center with said face plate, means including a plunger which is arranged to move said driving member out of engagement with said slot and to lock said spindle and to hold the same against rotation, and manually operable means to actuate said plunger without stopping the rotation of the .face plate to lock or release said spindle and center.

4. In a machine tool headstock, a base, a rotatable spindle thereon, a work supporting center carried by said spindle, a rotatable face plate, means to rotate said face plate, a movable radially extending key mounted on the end of said spindle, a keyway in said face plate which is arranged to mate with said key-to rotate said spindle and center with said face plate, yieldable means to maintain said key in driving position in said keyway, and manually operable means which is operable during rotation of said face plate to move said key against the tension of said spring to disengage said key from said keyway so that the spindle and center remain stationary while the face plate is rotated. I

5. In a machine tool headstock, a base, a r0- tatable spindle thereon, a work supporting center carried by said spindle, a rotatable face plate. means including an electric motor. drive and a clutch to rotate said face plate, a radially extending driving member on the end of said spindle, a slot in said face plate which is arranged to mate with said member to rotate said spindle and center with said face plate, means including a plunger carried by said frame and a mating recess in said spindle to facilitate locking said spindle, and a manually operable nut and screw mechanism arranged simultaneously to engage said pawl with said recess and to disconnect said key from said keyway so as to hold said spindle and center stationary while the face plate continues to rotate. 

